Assigstos



M. T. LOTHROP.

PYROMETER SWITCHi APPLICATION FILED 00T, 6, |919.

1,399, 1 34, Parma Dee. 6,

SELLER IBEARNG maaien.,

Specification of Letters atent.

Patented Ecc.

Application lerl Gctoher 6, 1919. Serial No. 328,675.

T 0 all 'zo/wm it may concern.'

Be it known that l, MARCUS T. Lornnor, a citizen of the United States, and a resident of the city of Canton, in the'county of Stark and State of Ohio, have invented a new and useful improvement in Pyrometer-Switches, of which the following is a specification.

My invention'relates to electric switches, especially to those adapted for connecting any onel of a series of thermo-couples or similar sources of electric energy to a meter. lt has for its principal objects to minimize the resistancevto the feeble current of the thermo-couple', to provide for the rapid reading of the temperatures of various units with a single instrument, to simplify the construction of the switch and to obtain` advantages hereinafter appearing. The invention consists in the parts and combinations of parts hereinafter described and claimed.

ln the drawings, which form party of this specification', and wherein like numerals refer to like parts wherever they occur,

yFigure 1 is a plan view of a switch embodying my invention as applied to a pyrometer system, and

Fig. 2 is a vertical section of the switch along the line 2-2 of Fig. 1, the thermocouples and meter being shown 'diagrammatic-ally.

A housing has a horizontal ledge 2 on` which is a base plate 3 of some material which is a non-conductor of electricity. The base plate has concentric annular channels or troughs 4: therein which are adapted to contain mercury. The base plate also has a plurality of pockets or depressions 5 arranged concentric'with said channels and adapted to contain mercury. The pockets are arranged. in pairs, the pockets of each*` pair receiving electrical conductors 7. y Said conductors 7 are connected to wires 6 leading to the opposite sidestof 'a thermo-couple or other source of electricity. The channels receive electrical vconductors 9 which lead to the terminals of a meter. l

A glass cover 8 with a hole in the center' rests on the housing'. A flange 9 at the top of the housing receives the ends of the arms of a spider 10. The under sides of the end portions of the spider arms are recessed to accommodate the marginal portion of 'the glass cover. The housing has recesses inits lower margin to receive the ends of the arms of a second spider 11. rlhe spiders at the top and bottom of the housing have bearings 12 for a vertical shaft 18. rlhe shaft has a switch arm le thereon provided with contact members 15 adapted to dip into the mercury in said channels and depressions.

The shaft is hollow and has a plunger 16 in the lower end on which the shaft is free to move. i The limits of the relative movement of the shaft and plunger are fixed by the cooperation of a slot 17 in the plunger with av pin 18 which passes through said slot and which is fixed in the walls of the shaft. A plug 19 which is screwed into the end of the lower bearing constitutes the support for the bottom of the vertical shaft. Preferably -an antifriction bearing 2O is interposed beplug 21 which is screwed therein. A spring 22 is interposed between the plunger and the plug. The spring is arranged to raise the shaft highenough to raise the ends of the contact members out of the mercury.

The shaft is provided with manually operable means for raising, lowering and rot-ating it. Preferably, the shaft has a handle or knob 23 attached to its upper end. The knob has an annular flange 24 thereon which has notches around its periphery adapted to engage pins 25 projecting from the arms of the-spider: In order to rotateithe shaft it is necessary to raise it far enough to clear' the tops of the pins. The notches of the flange are numbered. One of the pins'cooperates with the numbers to' indicate the location of the arm with reference tothe depressions.

When the handle is in its lowermost position, one end of each contact member dips into a pocket and the other end dips into one of the channels and a circuit is completed leading from the thermo-couple to a pocket of mercury, thence through one of the conducting membersr of the `handle to one of the channels of mercury, thence to the meter, from the meter back to the otherv channel, from the channel through the other conducting member of the handle to the sec- 1 ond pocket of mercury and thence back to Sa thermo-couple and each thermocouple has -its opposite sides connected to one of the and the meter, so that the amount of elecother uses.

tricity generated by the thermo-couple, and hence its temperature can bel indicated by the' meter. The meter may be graduated in units of heat, if desired. instead of units of electricity. The device is especially useful in measuring very weak currents as there is no danger of the contact points becoming pitted or dirty ;and thus weakening the current. Any foreign matter will float on top of the mercury. The'device is compact and enables one meter to beV used satisfactorily with a` large number of. thermo-couples.

I have described a preferred form of my invention as applied to a particular use, but the switch hereinbefore described has many It is especially vuseful wherever it is desired t'o connect'at will one electrical device to any one of a plurality of'such devices Itis obvious that changes may be made without departing from my invention and I do not wish to bek limited to the precise construction shown.

WhatI claim is:

l. An electric switch comprising a housing having a horizontal ledge on the inner side thereof, a plate on Said ledge having annular channels and depressions arranged concentrically and adapted to contain mercury, and a pivoted switch arm provided with contact members adapted to dip into said channels and depressions.

2. An electric switch -comprising a housing having a horizontal ledge, a base on said ledge, said base .having annular channels and depressions arranged concentrically and adapted to contain mercury, a spider supported on said housing, a glass cover for saidhousing having a hole inthe center thereof,.the under side of the marginal portions of said spider having recesses to receive said glass cover, and a rotatable and axially movable shaft concentric with said channels and depressions, said shaft being provided with a flange having notches around its pe riphery and pins on said spider in position t0 engage saidnotches, whereby said shaft can be rotated only after it has been raised far enough forlthe flange to clear said pins.

"3. An electric switch comprising depressions and annular channels arranged concentrically andadapted to contain mercury, a rotatable and axially movable shaft, said shaft having a switch arm thereon provided with contact members adapted to dip into said channels and depressions. and having a flange thereon having numbers around its periphery and an indicator for cooperating with the numerals on the flange to indicate the location of said switch arm with respect to said depressions.

'4. An electric switch comprising a base having depressions and annular channels arrangedconcentrically and adapted to contain mercury and a rotatable and axially movable shaft-v, said shaft having a switch arm thereon provided with contact members adapted todip into said channels and depressions. Y

5, An electric switch comprising a base having depressions and annular channels arranged concentrically and adapted to contain mercury and a switch arm having contact members adapted to dipinto said channels and depressions, said switch arm being4 rotatable about an axis concentric with-said depressions and channels and being movable axially with respect to said depressions and channels.

GAn electric switch comprising concentrically disposed contact members, a rotatablehollow shaft concentric with said Contact members, a` closure for the upper end of said shaft, a plunger in the lower end thereof, said shaft being slidable thereon, a switch arm supported by said shaft and havf ing members adapted to contact with said first mentioned contact members, and 'a spring in said shaft between said plunger and closure, whereby the contact members on said switch arm are held normally out of engagement with saidv first mentioned contact members.

7. A pyrometer system comprising a meter, a plurality of thermo-couples and means for selectively electrically connecting the respective thermo-couples to said meter, said means comprising mercury containing troughs and pairs of pockets, the opposite sides of each of said thermo-couples being respectively electrically connected to the contents of the membersof one of said pairs of pockets, and the contents of said troughs being, electrically connected to opposite sides of said meter, and means for electrically connecting the contents of said pockets respectively to the contents of said troughs.

8. A pyrometer system' comprising a meter, aplurality of thermo-couples, and means for selectively electrically connecting the respective thermo-couples to said meter, said means comprising a plate having mercury containing channels and depressions arranged concentrically and means for selectively electrically connecting said depressions with said channels respectively.

9. A pyrometer system comprising a plurality of thermo-couples, a meter, and means for selectively electrically connecting said thermo-couples respectively to said meter, said means comprising depressions vand channels adapted to contain mercury, and means -for selectively electrically' con necting'any two of said depressions with saiel Ithe respective thermo-couples to said meter,

said means comprising mercury containing channels, and depressions arranged con centrically and means for selectively electrically connecting said depressions with said channels respectively, said means comprising a rotatable and axially movable shaft concentric With said channels and depressions and an arm projecting from said shaft and having contact members adapted to dip into said channels and depressions.

1l.` A pyrometer system comprising a plurality'of thermo-couples, a meter, and means for electrically connecting any of 'said thermo-couples to saidl meter at will,

said means comprising depressions and channels adapted to contain mercury and a switch for connecting any of saicldepre'ssions with said channels, said switch comprising an arm movable above said depressions and channels andcontact members on said arm adapted to dip into said depressions and channels.- f

Signed at Canton, Ohio, this 29th day or September,'l9l9 MARCUS T. LoTHRoP. 

